Women with polycystic ovary syndrome (PCOS), obesity, and insulin resistance experience increased rates of implantation failure, which contribute to the higher degree of poor pregnancy outcomes observed in these populations. The increased levels of estrogen and insulin observed in women with PCOS are thought to be important contributors to the pathogenesis of miscarriage, but the underlying mechanisms remain obscure. A growing body of data suggests that abnormalities in glucose homeostasis caused by increased insulin and estrogen levels and/or signaling, are significant contributors to the increased pregnancy failure in this population. In addition, the two hormones may be acting synergistically to alter glucose utilization. The multifactorial nature of PCOS makes it important to dissect the variables involved and understand their independent contributions to the disease as a whole. Therefore, the objective of this proposal is to further understand the molecular mechanisms of estrogen-mediated, insulin-independent changes in glucose uptake and metabolism in 1) the murine endometrial stromal cells and 2) embryo at the time of implantation. We propose that prolonged exposure to pathologic levels of estradiol interferes with glucose metabolism in the uterine endometrial stroma and preimplantation embryo, by two different mechanisms. In the uterus, estradiol differentially modulates glucose uptake by regulating the expression of specific glucose transporters in the progesterone-primed endometrial stromal cells. In the embryo, the prolonged exposure to estradiol leads to hyperphosphorylation of c-Jun NH2-terminal kinase (JNK), leading to inactivation of the insulin receptor substrate-1 (IRS1) and development of insulin resistance. The long term goal of this proposal is to dissect the effects of pathologically high levels of estradiol on glucose utilization. We will utilize in vitro systems to study estrodiol-mediated effects in the endometrial stromal cells and preimplantation embryos and then confirm our findings in an vivo model of increased estrogen signaling. We will analyze glucose transporter expression, glucose uptake and utilization, and insulin signalling in both the uterine stroma and the embryo. PUBLIC HEALTH RELEVANCE: Understanding of the hormonalregulation of glucose uptake and metabolism in the uterine stroma, as well as, in the embryo at this critical time will potentially progress into the development of novel pharmacologic interventions to increase the rate of successful pregnancies in women with PCOS.